Question

Un elev a cheltuit in patru zile o suma de bani,astfel in priima zi 20%din suma,a doua zi o patrime din rest,a treia zi o treime din noul rest,iar a patra zi 100 de lei.ce suma de bani a avut initial elevul?

Answer 1

a+b+c+d=x
a= x/5
 5x/5-x/5 = 4x/5 = rest
b= 1/4 * 4x/5= x/5
4x/5-x/5=3x/5
c=1/3*3x/5 = x/5
3x/5-x/5= 2x/5
d=100
d= rest
2x/5=100
2x = 500
x= 250

Verificare:
a= 250 : 5 = 50
250-50=200
b = 200 : 4 = 50
200-50 = 150
c = 150 : 3 = 50
150-50=100=d